Crystal detector, used in early crystal set radios. Designed by J. G. Balsillie, and made at the Shaw Works, Randwick, Sydney, Australia in 1913. The pyrite crystal in the holder was presented separately in 1925.

A detector is a rectifier that converts radio frequency voltages to direct current.

Physical Description

Brown insulating plate with brass fittings, which allow two sideways perpendicular movements achieved by two screws operated by knobs. A cup shaped holder contains grey material with wire arranged to contact the grey material. The height of the end of the wire can be adjusted by another screw.

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